Abstract: A total of 379 2-year-old ewes from 3 core breeding populations of superfine-type cashmere goats in Inner Mongolia were included in this study to assess the correlation between their main phenotypic traits （body size and fiber traits）. The results showed that there were differences between body size and fiber traits in 3 core breeding populations. The average fibre diameter of each population was all less than 13.99 pLm. There were significant differences in fibre length between 3 core breeding populations （P〈0.05） ：Alxa Right Banner Cashmere Goat Breeding Base （7.90 cm） 〉 Inner Mongolia Cashmere Goat Breeding Farm （7.53 cm）〉 Alxa White Cashmere Coat Breeding Farm （6.59 cm）. The fibre diameter was significantly and negatively correlated with fibre length （P〈0.05）, the cashmere thickness was significantly and positively correlated with fibre length and raw cashmere weight （P〈0.01）, and live body weight after rawing cashmere was significantly and positively correlated with body length and chest circumference （P〈0.01）. The regression equation of phenotypie traits to raw cashmere weight was Y1=44.99＋43.26X2＋ 2.80X6, and the regression equation of phenotypie traits to live body weight after tawing cashmere was Y2=5.48＋0.19Xs＋0.09X6.